Looping Sound Causes Engine Freeze

I'm making a sequel to a game I made a couple of years ago with Torque 1.21 - I'm now using Torque 1.3 and hanging out for 1.4!

ANYWAYS I got lots of things working as they should, and have now copied the Sound datablocks from my old version and put them in car.cs (my wheeled vehicle scripts) All sounds work except EngineSound which causes by frame rate to drop to about 1 frame a minute (which is impossible to exit in fullscreen mode, I can crash out of it in windowed mode, though very slowly!)

Not surprisingly its getting annoying! If I change the audio profile of my EngineSound to a non looping one the game runs but the sound doesn't work. All other sounds, impacts squeals etc work fine all the time, just Engine Sound is an issue...

Any advice on where I should look to fix this would be appreciated!

datablock AudioProfile(EngineNoise)
{
          filename="~/data/sounds/diesel.wav";
          description="AudioCloseLooping3D";
          preload= true;
};

If I change description to "AudioClose3D"; the game runs but with no engine sound.

It is that same script and same sound file that worked in my old version of the game...

Thanks
Nick